Apparatus for handling a curved continuous casting starting bar



1967 K. REINFELD ETAL 3,344,844

APPARATUS FOR HANDLING A CURVED CONTINUOUS CASTING STARTING BAR FiledAug. 10, 1964 2 Sheets-Sheet l FIG. "1

INVENTOR5 KURT REINFELD 6 JOSEPH ROKOP BY v f/zezr Z Oct. 3, 1967 K.REINFELD ETAL 3,344,844

'APPARATUS FOR HANDLING A CURVED CONTINUOUS CASTING STARTING BAR FiledAug. 10, 1964 2 Sheets-Sheet 2 i 7 5'9 9 7.9 INVENTORS Kl/E'T RE/NFELD 6B JOS'EPH EO/(OP Meir Z a:

United States Patent 3,344,844 APPARATUS FOR HANDLING A CURVED CON-TINUOUS CASTING STARTING BAR Kurt Reinfeld and Joseph Rokop, Pittsburgh,Pa., as-

signors to Koppers Company, Inc., a corporation of Delaware Filed Aug.10, 1964, Ser. No. 388,562 9 Claims. (Cl. 164-274) The present inventionrelates to the art of continuous metal casting and, more particularly,to improved apparatus and method for producing continuous metalcastrngs.

The casting of a continuous strand of metal involves pouring moltenmetal into a flow-through type of casting mold, which confines themolten metal and partially shapes it to a desired cross section, andwithdrawing the metal from the mold as an elongate continuous strand orbillet. The casting mold is usually established at a convenient fixedlevel above a working area, and a ladle of molten metal is transportedby a vehicle or crane to a position above the casting mold and machine.

Before teeming the ladle and starting the strand, it is first necessaryto temporarily close the bottom of the mold to prevent the molten metalfrom simply running through the open bottom end of the mold. The openbottom end of the mold is usually closed by means of a dummy bar orstarting bar, which is threaded through a customary set of pinch rollslocated below the mold for the purpose of driving the dummy bar orstarting bar up into the bottom of the mold and later withdrawing it.After the starting bar has been driven into the bottom of the mold, theclearance gap between the head end of the starting bar and the walls ofthe mold is then sealed with a suitable refractory material. The mold isnow ready to receive molten metal from the ladle and a preheatedtundish.

Once the mold is prepared to receive the molten metal, the ladle isteemed or discharged into a rectangular trough called a tundish locatedbetween the ladle and the mold and from which the metal flows directlyinto the casting mold. The molten metal first entering the mold isallowed to solidify and become fastened to the head end portion of thestarting bar. After the molten metal has risen to some predeterminedlevel in the mold, the mold may be oscillated or reciprocated to preventsticking of the casting to the mold walls, and the pinch rolls may beactuated to start withdrawing the starting bar and casting from themold.

The steel continues to solidify as the strand is withdrawn, and a thinskin, which forms on the surfaces of the strand adjacent the inner wallsof the mold, thickens as the metal is pulled through the mold. To hastencooling and to increase the thickness of the skin, the strand is usuallypassed through a cooling chamber located below the mold where it issprayed with water from an array of nozzles. The solidifying strand,still at red heat, is pulled by the pinch rollers from the mold insynchronism with the rate of pouring metal into the mold so that thelevel of the liquid metal in the mold is maintained at a substantiallyconstant level and the strand is formed in a steady continuous manner.At a convenient level below the mold the starting bar is disconnectedfrom the strand and the strand is cut into convenient lengths forsubsequent reduction in size.

Two general types of continuous casting machines are employed. One typeof machine is known as a vertical cut-off casting machine wherein thecasting is withdrawn in a vertical position and is cut to desiredlengths at some point below the mold. In such machines, a straight rigidstarting bar is used, and after the casting has descended and passedthrough the pinch rolls, the starting bar is disconnected from thestrand and is stored in a convenient position until it is needed for thenext casting. The other type of machine is called a horizontal cut-offcasting machine wherein the casting is bent from the vertical and isguided by a chute toward a horizontal attitude.

Two main types of horizontal machines exist; one employs a verticalroller apron above a set of pinch rolls and the other employs a curvedroller apron and no pinch rolls. A horizontal cut-off casting machinealso employs a set of straightener rolls between which the castingpasses and from which it emerges as a straightened horizontal casting.

Vertical cut-off casting machines require an installation which aregenerally too large to be practical or economical. Horizontal cut-oifcasting machines, on the other hand, obviously do not require as largean installation as the vertical cut-off machines and for that reasonthey are more practical and economical. On some horizontal machines, astraight rigid starting bar is used wherein the bar is bent andstraightened on each cast. However, repeatedly bending, straightening,and bending the rigid starting bar deforms it to such an extent that itis no longer useful.

It has been proposed heretofore to use articulated starting bars whichreadily bend and conform to the geometry of the curved roller apronstructure, without the attendant difiiculties of the straight rigid barwhich must be continually bent and straightened. One form of articulatedstarting bar, of the sort mentioned, is described in US Patent No.2,920,359. Such starting bars, however, after being disconnected fromthe strand, must still be removed and stored in some location near thecasting machine until they are to be used again. In the overalloperating time to make a casting, the time lost in picking up the storedstarting bar, threading it back into the machine, and the time todisconnect it and place it back in storage, can become a seriouseconomic factor.

The present invention relates to apparatus and method for handlingcurved rigid starting bars of a type useful in horizontal cut-oifcasting machine. In accordance with the present invention, there isprovided a curved starting bar supporting structure, which adjacently ispositioned opposite the discharge end of a horizontal cutolf continuouscasting machine, and on which a curved rigid starting bar may beconveniently stored when not in use. In a further aspect of the presentinvention, straightener rolls engage the curved rigid starting bar anddrive it upward into operative engagement with the mold and withdraw itand the casting from the mold; the straightener rolls incorporating anovel mechanism for disconnecting the head end of the starting bar fromthe casting.

For a further understanding of the present invention and for advantagesand features thereof, reference may be made to the following descriptiontaken in conjunction with the accompanying drawings forming a part ofthis application in which:

FIG. 1 is a schematic elevational view of a horizontal cut-01fcontinuous casting machine incorporating an embodiment of the presentinvention;

FIG. 2 is a schematic view, partly in section, showing the head end ofthe starting bar in mated relationship to a casting mold;

FIG. 3 is a schematic view, partly in section, showing the head end ofthe starting bar and the casting in relation to the disconnectapparatus; and

FIG. 4 is a schematic view, partly in section, showing the starting bardisconnected from the casting.

Referring to the drawings, FIG. 1 illustrates a portion of a continuouscasting machine including a plurality of vertical columnar members '11,which are fixed to and rise above a working floor or ground level 13,and which support a plurality of horizontal girders 15 and 17 formingworking support levels above the floor or ground level 13. The upperhorizontal girders 17 support a conventional movable tundish 19, whichis supported by or suspended from a suitable support carriage 21 that isrollable on the horizontal girders 17.

A conventional ladle 23 is shown in an operative position directly abovethe tundish 19. The ladle 23 is supported in a conventional manner by anarrangement of cables 25. A conventional spill-over box 26 is alsosuspended from the upper horizontal girder 1'7 and below the tundish 19.

Below the tundish'19 and ladle 23, there is a continuous type ofvertical flow-through casting mold 27, which is established and fixed onthe lower horizontal girders 15. Beneath the mold 27, there ispositioned a conventional type of curved roller apron structure 29,having a typical water cooling spray section enshrouded by an enclosure30. a a

It is generally desirable to support the roller apron structure 29 on asuitable framework 31, which includes a plurality of wheels 33 that bearand roll upon suitable rails (not shown) fastened to the working flooror ground level ISIThfl apron structure 29 and framework 31, may bereadily maintained in an operative position, about where shown in FIG.1, by means of latch arms 35, which are pivotally connected to theupright columnar members 11, and which engage suitable latch pins 37fixed t the framework 31.

The arcuate roller apron structure 29 includes a plurality of spacedapart guide rollers 39, upon which the casting is supported as it iswithdrawn from the mold. The apron structure is positioned, preferably,so that the upper end is substantially vertical and adjacent the bottomof the fixed mold 27. The lower end of the apron structure extendsgenerally horizontally and at a convenient level above the working flooror ground level 13. Moreover, the curvilinear axis of the apronstructure is generally coplanar with the vertical axis of the mold, thetundish, and the ladle.

Preferably, the axis of the apron structure, at the lower horizontalend, is at substantially the same level as a first entrance set ofstraightener rolls 41, in a straightener apparatus 43, which is fixed tothe working floor or ground level 13. The straightener apparatus 43 alsoincludes a second exit set of straightener rolls 45, which areadjustable and movable vertically by means of a suitable ram cylinder 47and link mechanism 49, mounted conveniently on the straightenerapparatus, about as shown in FIG. 1. a

Adjacent to and just beyond the vertically movable straightener exitrolls .45, there is a triangular shaped stop bar 51 (see FIG. 3), whichis mounted rigidly to the frame of the straightener apparatus 43 in amanner such that the stop bar 51 is generally perpendicular to the planeof the casting machine. Also, there is mounted near the upperstraightener exit rolls 45, a conventional roller type limit switch 53,which is for a purpose to be described hereinafter.

To the right of the straightener apparatus .43, as viewed in FIG. 1,there is a conventional casting take-off apparatus 55, on which thestraightened casting is supported as it moves toward a conventionalcut-off mechanism, not shown.

Just above the casting take-off apparatus 55, there is provided anarcuate starting bar rack structure 56, the

.axis of which is substantially coplanar with the axis of the rollerapron structure 29 and the casting mold 27. The starting bar rackstructure 56 includes a pair of arcuate spaced apart parallel plates57,- 59, which may be maintained in such relation by being fixed to thehorizontal girders 15, 17, and to a plurality of vertical supportcolumnar members 61, 63, or in any other appropriate manner.

Between the spaced apart plates 57, 59, there may be mounted, in anysuitable manner, a plurality of guide rollers and support rollers 67,which are conveniently disposed oppositely and in spaced apart relation,about as shown in FIG. 1. The rollers 65, 67 are spaced apart a distancesufiicient to accommodate a curved starting bar 77, when the same isdisposed therebetween in a manner to be described hereinafter.

Above the upper horizontal girder 17, there is provided a conventionaltype sheave 69, which may be mounted in a vertical position, about asshown in FIG. 1, in a suitable bearing support 71 which may be fixed tothe columnar members 11. Below the sheave 69, there is provided asuitable hoisting mechanism 73, which may be conveniently powered by anelectric motor 75; both of which are fixedly mounted on the lowerhorizontal girders 15. The hoisting mechanism 73 is positioned,preferably, so that a hoisting cable 75, that is wound on the hoistingdrum, passes over the sheave 69, and is connectable to a suitablejoining eye 74, fixed in one end of the curved starting bar 77. Thecurved startting bar 77 is shown in its stowed position in FIG. -l, fromwhich position it is readily removable at the commencement of a casting,as will be described hereinafter.

Referring to FIG. 3, the lower end, or what is actually the head end ofthe starting bar 77, includes first and second body portions 79, 81 thatare detachably connected together. The first body portion 79 has a crosssection that is generally rectangular or square and, a length which issubstantially equal to the width of the casting. The first body portion79, moreover, has a plurality of slots 83, which have a generallyY-shape configuration, similar to that shown in FIG. 3. There isprovided in the right hand wall forming the vertical leg of the Y,another rectangular slot 85. A bolt-like member 87 is fixed to andprojects outwardly from the body portion81 in such a manner that theshank of the bolt 87 is received in the slot 85, and the head of thebolt is received in the slot 83. A similar bolt-like member 89 is fixedto and projects from the first body portion 79.

As may be seen in FIG. 2, when the head end portion of the starting baris positioned in mated relationship with the casting mold, the bolt-likemember 89 projects into the bottom portion of the mold and becomes fixedto the solidified initial portion of the casting, when it'is poured.Each of the bolt-like members 87, 89 may be readily maintained in itsrespective body portion 81, 79, by means of suitable keeper pins 91, orin any other appropriate manner. To facilitate disconnecting the firstbody portion 79 from the second body portion 81, the upper part of thesurface of the body portion 79, which abuts the body portion 81, iscurved, about as shownin FIGS. 3 and 4.

Referring to FIG. 1, it is convenient to assume-thata continuous castinghas just been completed and that another is to be commenced. Thestarting bar 77 at this time is in its stowed position in the'startingbar rack structure 56, and it is held in this stowed position bythehoisting cable 75 and hoisting mechanism 73. The casting machine may beconveniently operated from a control console or panel 99 located on thelower horizontal girders 15, at which location, an operator regulatesand controls the power output from a power unit 101, convenientlylocated nearby, to operate the casting machine.

The exit straightener rolls 45 are first raised to the position shown inFIG. 3, and then opened or separated a distance great enough to admitthe starting bar 77, which, at the same time, is being lowered from therack structure until the head end of it passes between the exitstraightener rolls 45 and between the entrance straightener rolls 41.The entrance straightener rolls 41 may then be actuated to drive thestarting bar 77 upward toward the mold 27.

It will be noted that the hoisting cable 75, as it pays out to lower thestarting bar, may be guided by a suitable guide roller 103, fixed to thestarting bar rack structure, and by the other guide rollers 65. Thestarting bar 77 is driven upward by the straightener rolls 41 until thehead end abuts the mold in mating relationship, about as shown in FIG.2. The joint between the mold and the head end may now be suitablysealed with a suitable refractory material to prepare the mold toreceive molten metal. The ladle, with molten metal therein, maythereuponbe teemed, and the metal flows into the tundish and into themold to initiate the casting.

After the casting has become inseparably connected to the bolt-likemember 89, the straightener rolls 41 may be reversed to withdraw thestarting bar and the casting from the mold. The starting bar will followthe curvature of the apron structure to which it is conformable, and thelower end of the starting bar again passes between the spaced apartvertically movable exit straightener rolls 45. The starting bar willthen enter between the rollers 65, 67 in the starting bar rack structure56. The curved roller apron structure and the starting bar rack supportstructure have, peferably, the same curvature so that there will be nobending forces exerted on the starting bar. The entrance straightenerrolls 41 continue to withdraw the starting bar and casting from the moldat substantially the same rate of speed as the casting is being formedin the mold. It will be appreciated by those skilled in the art, that inthe present invention there is no need to employ the usual set of pinchrolls which ordinarily engage the starting bar and drive it into themold, and later withdraw it and the casting from the mold. In thepresent invention, the starting bar, being a curved rigid member, may bereadily moved forward and backward by the straightener rolls. Onepurpose of the straighteners rolls is to advance and retract the curvedstarting bar without deforming it. So, too, the straightener rolls laterengage the casting when it has grown sufiiciently in length and passesthrough the straightener rolls. By the time the straightener rollsengage the casting, it is solid throughout and there is little or nodanger of inducing cracks, flaws and other defects.

After the head end of the starting bar and casting have passed throughthe exit straightener rolls 45, and are in 'a position about as shown inFIG. 3, a limit switch, not shown, is actuated by the roller contactmember 53 falling into one of the Y-shaped slots 81. The downwardmovement of the roller contact member causes the ram cylinder 47 to movethe pivotal link member 49 so that the straightener rolls 45 moverapidly downward. In doing so, they exert a downward force on the end ofthe casting and the starting bar to which it is connected. However thetapered end portion of the starting bar bears against the stop bar 51and is restrained from downward movement. Consequently, the bolt-likemember 87 becomes disengaged from the slots 83, 85 and the first bodyportion 79 is separated downwardly from the second body portion 81.

' During the downward motion of the rolls 45 to disconnect the castingfrom the starting bar, the hoisting mechanism 73 is actuated to exert apulling and restraining force on the starting bar which is sufficient tohold it, and to advance it upwardly further into the storage rack. Afterthe casting has been disconnected, it will be straightened in the usualmanner and directed horizontally, about as shown in FIG. 4. The castingmoves toward the casting takeoff apparatus, mentioned previously; thedriving force. being exerted by the entrance set of straightener rolls41.

' After a'casting'has been completed, the same curved starting bar isreadily available and may be quickly positioned, as describedhereinbefore, to commence another casting.

We claim:

1. A starting system for a continuous metal casting machine having anarcuate. roller apron structure with 6 an entrance end adjacent thebottom of a fixed vertical flow-through casting mold and a discharge endoriented in a substantially horizontal direction, comprising:

(a) an arcuate rigid starting bar conformable to the curvature of saidarcuate roller apron structure;

(b) staightener apparatus adjacent the discharge end of said apronstructure and having a set of first roller members for advancing saidarcuate starting bar into mating relation with said casting mold and forcontrollably withdrawing said bar and casting from said mold, saidstraightener apparatus having a set of second movable vertically opposedrollers capable of operating upon said bar and casting;

(c) a starting bar support adjacent said straightener apparatus andsubstantially coplanar with said roller apron structure for receivingand supporting said starting bar;

(d) a limit switch actuatable at a predetermined moment after the endportion of said casting has passed between said vertically opposedrollers to move said rollers downward rapidly and disconnect saidstarting bar from said casting; and

(e) a hoisting mechanism fixed to said starting bar support and having acable connected to said arcuate starting bar whereby said starting barengages said starting bar support and said bar is maintained in saidsupport.

2. A starting arrangement for a continuous metal casting machine havingan arcuate roller apron structure with an entrance end adjacent thebottom of a fixed vertical flow-through casting mold and a discharge endoriented in a substantiallyhorizontal direction, comprising:

' (a) an arcuate rigid starting bar conform-able to the curvature ofsaid apron structure; and

(b) straightener rolls positioned adjacent the discharge end of saidapron structure and adapted to operate upon said arcuate starting barfor advancing the same into mating relation with said casting mold andcontrollably withdrawing said bar and casting from said mold.

3. A starting arrangement for a continuous metal casting machine havingan arcuate roller apron structure positioned with its entrance endadjacent the bottom of a vertical flow-through casting mold, and itsdischarge end oriented in a substantially horizontal direction,compnsmg:

(a) an arcuate rigid starting bar conformable to the curvature of saidarcuate roller apron structure; (b) straightener apparatus positionedadjacent the discharge end of said apron structure and having a set offirst roller members for advancing said starting bar toward said castingmold and controllably withdrawing said bar and casting from said mold,said straightener apparatus having a set of second Vertically movableroller members capable of operating upon said bar and casting;

(c) a stop bar fixed in relation to said vertically movable rollermembers and downstream therefrom; (d) an arcuate structure positionedadjacent said straightener apparatu and substantially coplanartherewith, said arcuate structure being conformable to the curvature ofsaid arcuate rigid starting bar and adaptable to support the same;

(e) means actuatable at a predetermined moment after an end portion ofsaid casting has passed between said vertically movable roller membersand said starting bar bears against said stop bar whereby saidvertically movable roller members descend rapidly and disconnect saidstarting bar from said casting; and

(f) means for supporting and maintaining said starting bar in saidarcuate structure.

4. A starting arrangement for a continuous metal casting machine havingan arcuate roller apron structure. positioned with its entrance endadjacent the bottom of a vertical flow-through casting mold, and itsdischarge end oriented in a substantially horizontal direction,comprising:

(a) an arcuate rigid starting bar conformable to the curvature of saidarcuate roller apron structure;

(b) means for advancing said starting bar toward said casting mold andcontrollably withdrawing said bar and casting from said mold;

(c) an arcuate structure adjacent said starting bar ad vancing means andsubstantially coplanar with said apron structure, said arcuate structurebeing conformable to the curvature of said arcuate rigid starting barand adaptable to support the same;

(d) means actuatable at a predetermined moment after said bar has beenreceived by said arcuate structure to disconnect said casting from saidstarting bar; and

(e) means for maintaining said starting bar in said arcuate structure.

5. A continuous metal casting machine comprising:

(a) a vertical flow-through casting mold;

(b) an arcuate roller apron structure positioned with its entrance endadjacent the bottom of said mold and its discharge end oriented in asubstantially horizontal direction;

(c) an arcuate rigid starting bar conformable to the curvature of saidarcuate roller apron structure; (d) means for advancing said startingbar toward said casting mold and controllably withdrawing said bar andcasting from said mold;

(e) an arcuate structure adjacent said starting bar actuating means andsubstantially coplanar with said apron structure, said arcuate structurebeing conformable to the curvature of said arcuate rigid starting barand adaptable to support the same;

(i) means actuatable at a predetermined moment after said bar has beenreceived by said arcuate structure to disconnect said casting from saidstarting bar; and

(g) hoisting means to elevate and maintain said starting bar in saidarcuate support structure.

6'. A starting arrangement for a continuous metal casting machine,comprising:

(a) a rigid arcuate starting bar;

(b) an arcuate structure adjacent to and lying substantially in thevertical plane of said machine for receiving and supporting said arcuatestarting bar; and

(c) means for maintaining said starting bar in an elevated positionadjacent said machine and for lowering said starting bar from saidarcuate structure to operatively coact with said machine.

7. A horizontal cut-oil continuous metal casting machine comprising:

(a) a vertical flow-through casting mold;

(b) an arcuate roller apron structure for supporting said casting;

(c) a rigid arcuate starting bar conformable to and cooperative withsaid apron structure;

(d) means actuatable at a selected time to disconnect said starting barfrom said casting; I

(e) an arcuate structure adjacent to and lying substantially in thevertical plane of said machine for supporting said arcuate starting barin an elevated position after the same has been disconnected from saidcasting and maintaining said bar adjacent said machine in such a mannerthat said starting bar may be lowered from said support structure tooperatively I coact with said machine; and

(f) powered means to elevate and maintain said starting bar in saidsupport structure.

8. A horizontal cut-off continuous metal casting machine comprising:

(a) a vertical flow-through casting mold;

(b) an arcuate roller apron structure capable of sup- (e) meansactuatable by said starting bar for disconnecting said starting bar.from said casting;

(f) an arcuate structure adjacent to and lying substantially in thevertical plane of said machine for supporting said arcuate starting barin an elevated position after the same has been disconnected from saidcasting and maintaining said bar adjacent said machine in such a mannerthat said starting bar may be lowered from said support structure tooperatively coact with said machine; and

(g) means for elevating and maintaining said starting bar in saidsupport structure.

9. A continuous metal casting machine of the horizontal cut-ofi typecomprising:

(a) a vertical flow-through casting mold;

(b) an arcuate roller apron structure positioned with one end adjacentthe bottom of said mold and with the other end oriented in asubstantially horizontal direction, said apron structure and said moldbeing substantially coplanar;

(c) a rigid arcuate starting bar conformable to and cooperative withsaid apron structure and said mold;

(d) straightener apparatus positioned adjacent the discharge end of saidapron structure and having a set of first powered roller membersengageable with said starting bar for driving said bar toward saidcasting;

mold and controllably withdrawing said bar and casting from said mold; V

(e) a set of vertically movable roller members adjacent saidstraightener apparatus and positioned downstream therefrom which arecapable of operating upon said casting to exert a downward forcethereon;

(f) an arcuate structure adjacent to and lying substantially in thevertical plane of said machine for supporting said arcuate starting barin an elevated position after the same has been disconnected from saidcasting and maintaining said bar adjacent said machine in such a mannerthat said starting bar may be lowered from said support structure tooperatively coact with said machine;

(g) means for restraining said starting bar from downward movementrelative to said casting;

(h) means for moving said vertically movable roller members downward ata predetermined moment and disconnecting said casting from said startingbar; and

(i) hoisting means connected to said starting bar for elevating the samein said arcuate structure after said bar has been disconnected from saidcasting, and maintaining said bar in a selected position in said arcuatestructure.

References Cited 1. SPENCER OVERHOLSER, Primary Examiner.

R. S. ANNEAR, Assistant Examiner.

2. A STARTING ARRANGEMENT FOR A CONTINUOUS METAL CASTING MACHINE HAVINGAN ARCUATE ROLLER APRON STRUCTURE WITH AN ENTRANCE END ADJAENT THEBOTTOM OF A FIXED VERTICAL FLOW-THROUGH CASTING MOLD AND A DISCHARGE ENDORIENTED IN A SUBSTANTIALLY HORIZONTAL DIRECTION, COMPRISING: (A) ANARCUATE RIGID STARTING BAR CONFORMABLE TO THE CURVATURE OF SAID APRONSTRUCTURE; AND (B) STRAIGHTENER ROLLS POSITINED ADJACENT THE DISCHARGEEND OF SAID APRON STRUCTURE AND ADAPTED TO OPERATE UPON SAID ARCUATESTARTING BAR FOR ADVANCING THE SAME INTO MATING RELATION WITH SAIDCASTING MOLD AND CONTROLLABLY WITHDRAWING SAID BAR AND CASTING FROM SAIDMOLD.